Glossary entry for "Pythagoras’ theorem"

Pythagoras’ theorem

For a right-angled triangle

• The square of the hypotenuse of a right-angled triangle equals the sum of the squares of the lengths of the other two sides.
• In symbols, c² = a² + b².

The converse

If c² = a² + b² in a triangle ABC, then ∠C is a right angle.​